What is "serverless" computing?

The phrase “serverless” doesn’t mean servers are no longer involved. It simply means that developers no longer have to think "that much" about them. Computing resources get used as services without having to manage around physical capacities or limits.
Let's take for example AWS Lambda. "Lambda allows you to NOT think about servers. Which means you no longer have to deal with over/under capacity, deployments, scaling and fault tolerance, OS or language updates, metrics, and logging."

Para - Flexible and lightweight backend service for rapid prototyping, based on open source software.

Backand - One platform to develop and run multi-cloud Serverless applications.

wolkenkit - wolkenkit is a CQRS and event-sourcing framework for JavaScript and Node.js which fits perfectly with domain-driven design (DDD).

Kuzzle - High performance cloud agnostic backend solution including persistence, authentication, realtime database and geofencing with a full featured cluster mode.

Hosting and code execution in the cloud

Amazon Lambda - Run code without thinking about servers. Pay for only the compute time you consume.

Google Cloud Functions - Lightweight, event-based, asynchronous compute solution that allows you to create small, single-purpose functions that respond to cloud events without the need to manage a server or a runtime environment.

Jets - Ruby Serverless Framework for AWS. Jets allows you to create serverless applications with a beautiful language: Ruby. It includes everything required to build an application and deploy it to AWS Lambda.

Kappa - a command line tool that (hopefully) makes it easier to deploy, update, and test functions for AWS Lambda.

OWASP ServerlessGoat - OWASP ServerlessGoat is a deliberately insecure realistic AWS Lambda serverless application, maintained by OWASP and contributed by PureSec. Install ServerlessGoat and learn about the vulnerabilities, how to exploit them, and how to remediate each issue. Installation is just a 1-click through the AWS Serverless Application Repository

Awesome-Serverless-Security - A curated list of awesome serverless security resources such as (e)books, articles, whitepapers, blogs and research papers.

Docker in Action, Second Edition A book that teaches you the skills and knowledge you need to create, deploy, and manage applications hosted in Docker containers and it has been fully updated with new examples, best practices, and entirely new chapters.